1. Field of the Invention
This invention relates generally to the field of drywall installation and more particularly to drywall endcaps for exterior drywall corners.
2. Description of Related Art
The use of gypsum drywall board in modern construction is well known. Manufactured drywall sheets are nailed to studs to form interior walls and ceilings. Before these sheets can be painted or textured, the joints must be taped and sealed with joint sealing compound (drywall mud). Taping (known as stringing) is a tedious process since first tape and mud must be dispensed with a tool known as a bazooka, then the worker rolls and glazes the tape while the mud is wet. As the tape strings out, it has a tendency to pull in the direction of motion.
Many seams are finished with an old product known as flex bead. This is first attached over the seam and coated with drywall mud. After the mud is dry, it is sanded and finished, and then painted or textured.
A new system of interior and exterior flex-trim material has been invented that can be constructed from a laminate of paper-plastic-paper that is finished as soon as it is installed (see U.S. Pat. No. 6,148,573). This material can be beveled so that its edges can be xe2x80x9ckilledxe2x80x9d with a small amount of drywall mud and a wide blade, or other, tool. This leads to a finished seam or corner with the material blending into the drywall sheet. The finished seam or corner is ready to paint or texture as soon as the mud drys.
Using this new technology with outside corners leaves a perfect drywall corner except that the top corner is unfinished. What is badly needed is a junction piece similar to the new technology to complete the corner.
The present invention relates to a system of endcaps that are used to finish exterior corners making outer 90 degree angles or exterior corners making one interior 90 degree angle. The corners can be square or bullnose and can be made to mate with two or three pieces of the flex-trim type technology. While 90 degrees is given as an example, any angle is possible. The corners can be laminate or single layer pieces that have an outside surface prepared to receive paint or texture. The corners can have tabbed edges that adhere to drywall mud for contact with drywall and built up members that can be tapered to match any taper in the flex trim product and to merge into the surrounding drywall. In the case where the endcaps of the present invention are laminar, they can be made of two or three layers of material. The inner layer can be a material made to contact drywall and to stick to wet drywall mud. This can be any fibrous material, in particular drywall paper. The next layer can be semi-rigid durable material such as high impact plastic which can be tapered to a thin edge. The surface of the plastic can be prepared to directly receive paint or texture, or there can be a third layer in the laminate which can be a fibrous material like cup stock paper or any other material capable of directly receiving paint or texture.